1. Technical Field
The present invention relates generally to emergency warning systems, and more particularly, to a system for selectively providing a warning of the threat of imminent severe weather, such as a tornadoes, in a specific area.
2. Statement of the Problem
Most of the tornado warning systems in use today are leftover relics of the Civil Defense System era. Some have been upgraded and expanded and some have not. These systems employ sirens which were not originally designed to warn people inside their homes in noisy, violent weather conditions such as those that precede and accompany tornadoes. One way of overcoming this limitation would be to install many times the number of sirens currently used in these systems, but this solution is cost prohibitive. Even in areas with modernized, well-maintained siren systems, vast numbers of people simply cannot hear the sirens from inside their homes or offices. As a result, tornadoes continue to kill and injure large numbers of people who would have taken shelter if they had received a proper warning.
Beginning in the late 1950's, the National Weather Service (NWS), then the U.S. Weather Bureau, started developing a voice radio broadcast systems to provide more frequent and specialized weather information to the general public and users with unique weather needs than was available from the commercial radio and television services. Coverage from stations during this period was primarily confined to large urbanized cities and along the coasts. The service was eventually named NOAA Weather Radio (NWR). Starting in 1985 the NWS began inserting special digital codes at the beginning and end of any NWR message about a life or property threatening event. The intent was to ultimately transmit a code with the initial broadcast of all NWR messages. This system evolved into what is known today as NWR-Specific Area Message Encoding (“S.A.M.E.”).
The NWR-SAME process is achieved using an encoder panel consisting of a number of buttons representing the functions to be performed, types or content of messages, the affected areas, and valid time of the message. A microprocessor in the panel interprets button active status and creates the proper codes and places them at the beginning and end of each message. The panel is electronically connected to the various types of message programming and playback consoles used by the NWS to broadcast messages over the NWR transmitters. In the S.A.M.E. system, the geographic area affected by the message is encoded to allow for subdividing the target area into smaller partitions in the case of very large or uniquely shaped area, or because of widely varying height, climate, or other geographic features. It should be noted, however, that the S.A.M.E. system has neither the intention nor the provision for subdividing a target area according to demographic criteria such as that used for locating warning sirens.
As structured, a S.A.M.E. message has a county indicator code that is capable of being subdivided into a maximum of 9 sub-areas. Furthermore, weather forecast information for a given area is generated only at one of the relatively few NWS Weather Forecast Offices, which, being limited in number, are thus not able to provide the granularity of information (both temporal and geographic) available to weather observers in each local community. The National Weather Service presently plans to create a total of 121 Weather Forecast Offices to provide all warning and forecast services for the area consisting of the 50 States and the U.S. territories. This means that, on the average, there are fewer than three forecast offices per state. In fact, Kansas, which incurs the fourth most tornadoes of any of the states, has only three such offices to cover an area of over 82,000 square miles. It is clear, therefore, that these three offices simply cannot provide timely warnings having anywhere near the geographical precision afforded by the much larger number of entities located in individual communities. Visual sightings are frequently the only manner in which fast moving and relatively localized severe weather phenomena, such as tornadoes and flash floods, can be reported with sufficient accuracy to provide a useful warning. Where transient, localized weather phenomena is concerned, it is therefore even more important, if not essential, that warnings be issued by authorities in close proximity to the threatening weather event.
Furthermore, the warning method employed by the NOAA NWR system does not distinguish between an actual tornado warning (a tornado has actually been sighted) versus a severe storm that has a high probability of producing a tornado. This is because NOAA must rely on technical weather data from radar and satellite, and the data from these sources cannot confirm that a tornado has actually formed.